With the development of technology and the improvement of people's living standard, cars, mobile phones, computers and digital cameras have been essential items for people's living, outing and travelling. These items are all battery-powered, and thus, they may completely lose their functionality when the power source is used up, and thus is inconvenient for people's life. Therefore, for each product, the manufacturer usually provides a corresponding charger to convert the 220V municipal electricity into a direct current power source of a voltage suitable to recharge the product, but this kind of charger can not meet outdoor recharging demands. For vehicles, it frequently occurs that the vehicle can not be started, especially for the vehicle in a travel trip, it may be difficult to get started due to insufficient power or low temperature, which is inconvenient for the users.
A prior Chinese patent document CN 101685974A discloses a mobile power having a battery pack, a charging circuit, a MCU micro controller circuit and a DC-DC voltage regulating output circuit. The charging circuit has an input terminal that may be connected to an external power source, and an output terminal of the charging circuit is electrically connected to the battery pack. Moreover, the battery pack is electrically connected to the MCU micro controller circuit and the DC-DC voltage regulating output circuit, the MCU micro controller circuit is electrically connected to the charging circuit and the DC-DC regulator output circuit and controls the two circuits. The above technical solution has the following advantages: simple circuit schematic, smaller size, light-weight for carrying, easy for controlling, intelligence, low power consumption and versatility, rechargeability using municipal electricity, capability of charging a variety of electronic products with different output conversion terminals or being charged by these electronic products, convenience for managing, carrying and use. The prior patent application solves the problem of outputting power under various voltage levels and having a recharging function, but it can not be used as the vehicle starter because it does not have the high-current outputting capability. In addition, the output current according to the above patent application document is direct current. But in practice, many external equipments need alternating current input, thus the prior patent application failed to solve the problem of powering such equipments in emergency.